java-如何生成一个6位随机十六进制值

Question

I have a scenario in a Android app, where a random hexadecimal value has to be generated with 6 digits. (The range of values can be hexadecimal or integer values).

What is the most efficient way to do this? Do I have to generate a random decimal number, and then convert it to hexadecimal? Or can a value be directly generated?

Answer 1

    String zeros = "000000";
    Random rnd = new Random();
    String s = Integer.toString(rnd.nextInt(0X1000000), 16);
    s = zeros.substring(s.length()) + s;
    System.out.println("s = " + s);

Answer 2

You can use hex literals in your program the same way as decimal literals. A hex literal is prefixed with 0x . Your max value is FFFFFF , so in your program you can write

int maxValue = 0xFFFFFF;

Then you need to generate random numbers in that range. Use the Random class as you normally would.

Random r = new Random();
int myValue = r.nextInt(maxValue + 1);

Note the use of maxValue + 1 , because the upper bound for nextInt() is exclusive.

The final step is to print out your hex value.

System.out.printf("%06X", myValue);

Answer 3

SecureRandom random = new SecureRandom();
int num = random.nextInt(0x1000000);
String formatted = String.format("%06x", num); 
System.out.println(formatted);

Code Explain

1. this random object use SecureRandom Class method. this class use for generate random number.

    SecureRandom random = new SecureRandom();

2. next int num object store 6 hexadecimal digit random number

   int num = random.nextInt(0x1000000);

3. then output num as 6 digit hexadecimal number

   String formatted = String.format("%06x", num);